Fuel injection control valve



Feb. 17, 1959 ZUBATY FUEL INJECTION CONTROL VALVE 2 Sheets-Sheet 1 Filed Nov. 23,. 1956 ATTORNEY Feb. 17, 1959 ZUBATY 2,873,956

FUEL INJECTION CONTROL VALVE Filed Nov. 23, 1956 2 Sheets-Sheet 2 IN V EN TOR.

- ATTORNEY United States Patent 6 2,873,956 FUEL INJECTION CONTROL VALVE Joseph Zuhaty, Flint, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 23, 1956, Serial No. 624,045 4 Claims. (Cl. 261-69) The present invention relates to a fuel injection system of the type in which fuel is supplied to the fuel distributing system in a quantity in excess of that required by the engine under any given operating condition. In such a system it is the practice to provide a valve means which controls the quantity of excess fuel which is bypassed around the distributing system and which valve therefore determines the quantity of fuel available to the distributing means.

The present invention is particularly directed to a novel type bypass control valve in which the quantity of fuel bypassed is dependent on the resultant of a plurality of control forces. In general the actuation of the subject control valve is dependent upon the load on the engine and the mass of air flowing to the inlet manifold.

The present invention is illustrated with a fuel injection system of the type in which fuel under pressure is supplied to a distributing mechanism which supplies fuel to an inlet manifold or to the individual engine cylinders, and which system includes a bypass conduit returning excess fuel to the fuel source. The subject bypass control valve is disposed in the bypass conduit and therein controls the quantity of fuel being returned to the fuel source in accordance with manifold depression as well as the mass of air flowing through the air induction passage and thus automatically controls the fuel flowing to the engine.

The invention will hereinafter be described in detail.

In the drawings:

Figure 1 is a diagrammatic representation of a fuel injection system embodying the subject bypass control valve; and

Figure 2 is an enlarged detail view of the subject control valve.

Referring to Figure l, a fuel reservoir is shown at and includes a fuel .pump 12. Fuel under pressure is de livered to a supply line 14 which communicates with a fuel distributing mechanism indicated generally at 16. Distributing mechanism 16 includes a passage 18 having a branch 20 which leads to a distributing device 22 which delivers fuel to the passages 24 leading to an inlet manifold 26 and the respective engine cylinders.

The fuel distributing system may be of the timed or continuous injection type as preferred. The illustrated fuel distributing system is of the type described in my copending application Serial No. 623,242, filed November 19, 1956 and, briefly, provides timed injection at low engine speeds and continuous injection at high speeds.

A return passage 28 also communicates with passage 18 and in turn communicates with a bypass control valve indicated generally at 30 from whence passage 32 returns excess fuel to the reservoir 10.

As may be seen generally in Figure l, the bypass control valve 30 includes a diaphragm 34 having a valve member 36 fixed centrally thereof and which valve is adapted to variably control the flow of fuel through bypass or return passage 28. The diaphragm 34 is urged up- Wardly by a spring 38 which tends to close or limit the r 2,873,956 I Patented Feb. 17, 1959 ice flow through the bypass valve mechanism thereby causing a maximum amount of fuel to be supplied to the fuel dis tributing mechanism 16. v

Diaphragm 34 divides the bypass control mechanism easing into a pair of chambers 40 and 42. Chamber 42 communicates with the inlet manifold through a passage 44 while chamber communicates with an air induction conduit 46 through a conduit 48. A throttle or flow controlling valve 50 is disposed in the air induction passage 46 so that conduit 44 communicates with the inlet manifold posteriorly of the throttle valve whereas conduit 48 communicates with the induction passage anteriorly of the throttle valve. A venturi 52 is formed in the induction passage 46 whereby the quantity of air flowing through the induction passage creates a vacuum signal in conduit 48 proportional thereto.

Thus, as the manifold vacuum decreases, as is the case when the engine is operating under a heavy load, spring 38 tends to close valve 36 to thereby supply additional fuel to the engine as required. On the other hand, with a high manifold vacuum, indicative of a light engine load, the vacuum force in chamber 42 tends to move the diaphragm downwardly against the force of spring 38 to open the bypass valve 36 reducing the quantity of fuel available to the distributing mechanism 16.

An additionalforce is acting on diaphragm 34 in chamber 40 where a vacuum force is present which is proportional to the mass of air flowing through venturi 52. Under conditions where a large quantity of air is flowing through venturi 52, indicative of a need for increased fuel flow to the engine, a high vacuum signal will be present in conduit 48 and chamber 40 tending to move the diaphragm and valve upwardly to close bypass valve element 36 making more fuel available to the fuel distributing means 16. As the throttle valve is moved from an open to a closed position, progressively less air will flow through the venturi 52 thereby decreasing the force in chamber 40 and at the same time permitting the high manifold vacuurn to move the diaphragm 34 and valve element 36 downwardly to bypass more fuel to the reservoir 10.

The bypass control valve 30 is thus differentially controlled by forces directly proportional to engine load, as reflected by manifold vacuum, and the mass of air flowing through the induction system.

It is to be understood that the representation of bypass valve 30 in Figure 1 is diagrammatic in nature and a preferred form of the valve as it might actually be constructed is shown in Figure 2. Referring to Figure 2, bypass control valve 30 includes a plurality of casing members 60, 62 and 64. Casing members 62 and 64 are dish shaped andperipherally clamp diaphragm 34 therebetween so as to define the valve actuating chambers 40 and 42. Valve element 36 is centrally fixed to the diaphragm 34 which includes a pair of centrally disposed dish shaped washer members 66-and 68. Valve 36 projects through an opening 70 in the upper casing 62 and terminates.

within casing 60.

Casing 60 includes a large bore 72 and a small concentrically disposed bore 74. Fuel inlet and outlet passages 76 and 78 are formed in casing 60 and respectively communicate with return or bypass passages 28 and 32. An orifice member 80 is threadedly disposed within bore 74 and includes a conical opening 82 therethrough with which the tapered end 84 of valve element 36 is adapted to coact to variably control the quantity of fuel flowing through the bypass control mechanism. As valve 36 moves upwardly the orifice opening 82 is restricted and as the valve moves downwardly the opening increased.

-In order to isolate and seal bore 72 from actuating chamber 40 and thereby prevent the leakage of fuel thereinto, a flexible diaphragm 88 is fixed to valve 36 through a sleeve 90 and at-the same time fixed to casing 62 through a clamping member 92.

A plug 94 is threadably mounted in lower casing 64 and provides an adjustable seat 96 for one end of spring member 38, the other end of which biases against the diaphragm 34 through a dished member 98. Centrally disposed in plug 94 in axial alignment with valve element 36 -is a screw which is axially adjustable to variably limit the open position of the valve element '36 and hence the amount of opening of orifice-$2. Screw 100 has a nut 102 adapted to lock the latter in an adjusted position. It is apparent that by axially adjusting plug 94 the'rate of spring 38 and hence the force tending to move valve element '36 toward a closed position may be varied. It is also apparent that each adjustment of plug 94 requires a corresponding adjustment of screw 1% if the open size of orifice 82 is to remain constant.

. A cylindrical member .104 is fixed interiorly of-casing 64 and includes a radially-inwardly projecting flange 1% disposed at the upper end thereof. Flange 106 overlies a similar flange 1% formed on dished member 3 and thereby limits the upward movement of the latter member and in turn the upward or closing movement-of diaphragm 34 and valve element 36. The stop function performed by flanges 1G6 and 103 insures that influence of the comparatively high rate spring 38 will be controlled by the balance of forces between the spring of lesser rate 112 and the vacuum signal from the venturi 52.

An annular groove 110 is formed in the casing 62 and provides a seat for one end of a spring 112, the other end of which seats against reinforcing member 66 of diaphragm 34. p

A passage 114 is formed in casing 64 and includes a perforated disc 116 mounted upon an annular seat 118 formed therein. Disc 116 is biased against seat 118 through a spring 120. Passage 114 communicates with conduit 44, the other end of which connects with the inlet manifold posteriorly of throttle valve 5% as noted. The purpose of spring biased disc 116 is to give a different rate of actuation to the diaphragm 34 when the diaphragm is being moved downwardly under the influence of ahigh manifold vacuum as contrasted with the upward movement of the diaphragm under the influence of spring 38 or venturi vacuum. In other words, when manifold vacuum is high the downward movement of the diaphragm will be limited by flow through the perforations in disc 116. On the other hand, when the diaphragm 34- is being moved upwardly disc 116 will be lifted olf its seat against the force of spring 12th permitting more rapid movement of the diaphragm.

Casing 62 has a passage 122 formed therein which is adapted to communicate with conduit 4% to transmit a vacuum signal tochamber 4% which is proportional to the mass of air flowing through venturi 52 as already described.

In order to prevent hunting of valve element 36 under the influence of the constantly changing forces in chambers and 42, a disc member 124 is fixed to the valve through the sleeve 9i) and extends diametrically of bore 72 to an extent which is just short of touching the inner wall of the bore. Inasmuch as the bore 72 is filled with fuel, a requisite amount thereof must be transferred around the periphery of disc 124- thus delaying the movement of valve element 36. By this dash pot device mihuh: and inconsequential variations in the adjustment of the needle valve element 36 are avoided and a steadier operating characteristic imparted to the bypass control valve mechanism 30. V

While the bypass control valve 34} has been shown having three casing members, it is apparent that the casing members 6% and 62 may be combined as an integral housing in which a flexible diaphragm such as 88 would still be employed to separate the fuel chamber or bore 72 from the vacuum chamber 40. v p

Other structural modifications in the bypass control garages V H 4 valve 39 are possible within the intended scope of the present invention.

I claim:

1. A bypass control mechanism for an internal combustion engine fuel injection system, said mechanism comprising a pair of easing members, a diaphragm peripherally clamped between said members and defining an actuating chamber with each of said casing-members, fuel inlet and outlet openings disposed in one of said casing members, a valve means fixed to and movable with said diaphragm and cooperable with said fuel inlet opening .to vary the size thereof, means continuously urging said valve in a direction to limit the flow of fuel through said inlet opening, means communicating one of said chambers with an engine force tending to opensaid valve as the load of said engine decreases, means communicating the other of said chambers with a force tending to close said valve in proportion to the mass of air flowing through the engine, means separating said inlet and outlet openings from the actuating chamber in the associated casing member to provide a fuel chamber isolated'from the actuating chamber, and a disc member mounted for movement with said valve in said fuel chamber, fuel in said chamber being adapted to be transferred from one side of thedisc to the other to modify the rate of movement of said valve.

2. A bypass control mechanism for an internal combustion engine fuel injection system, said mechanism comprising a pair of casing members, a diaphragm peripherally clamped between said members and defining an actuating chamber with each of said casing members, fuel inlet and outlet openings disposed in one of said casing members, a valve means fixed to and movable with said diaphragm and cooperable with said fuel inlet opening to vary the size thereof, means continuously urging said valve in a direction to limit the flow of fuel through said inlet opening, stop means for limiting the closing movement of said valve to permit a limited quantity of fuel to flow through said valve mechanism at all times, adjustable stop means for limiting the opening movement of said valve, means communicating one of said chambers with an engine force tending to open said valve as the load of said engine decreases, means communicating the other of said chambers with a force tending to close said valve in proportion to the mass of air flowing through the engine, flexible means fixed to said valve and the casing having the inlet and outlet openings therein for separating said openings from the actuating chamber in the associated casing member to provide a fuel chamber isolated from the actuating chamber, and a disc member mounted for movement with said valve in said fuel chamber, fuel in said chamber being adapted to be transferred from one side ofthe disc to the other during the movement of said valve to modify the rate of movement of said valve. 7 r 1 3. A bypass control valve mechanism for an internal combustion engine fuel injection system, "said mechanism comprising a pair of dish shaped casing members; a diaphragm peripherally clamped between said casing members to define an actuating chamber respectively therewith; a valve element centrally fixed to said diaphragm and movable therewith, said valve element projecting through an opening in one of said casings; a third casing mounted upon the casing member through which said valve projects, said third casing having a large bore, and a small bore axially aligned with the large bore, an orifice member disposed between said bores, said valveineluding a tapered endadapted to project through said orifice and to vary the opening thereof, a fuel inlet opening formed in said third casing and communicating with said small bore, an outlet opening formed in said third casing and communicating with said large bore, means for sealing the large bore in said third casing from the actuating chamber in the subadjacent casing, an axially adjustable plug member threadably mounted in one of said casings and having an annular seat formed thereon, a retaining member disposed in the actuating chamber associated with said plug, a spring member disposed intermediate said annular seat and the retaining member for urging said diaphragm and valve toward an orifice closing position, stop means for limiting .the closing movement of said valve, passage means formed in one of said casings and adapted to communicate a force to the associated actuating chamber which is proportional to the mass of air flowing through said engine to move said valve toward a closed position, and a passage formed in the other of said dish shaped members and communicating the opposite side of said diaphragm to a force proportional to the load on said engine force adapted to move said valve toward an open position as said force increases.

4. A bypass control valve mechanism for an internal combustion engine fuel injection system, said mechanism comprising a pair of dish shaped casing members, a diaphragm peripherally clamped between said casing members to define an actuating chamber respectively therewith, a valve element centrally fixed to said diaphragm and movable therewith, said valve element projecting through an opening in one of said casings, a third casing member mounted upon the casing member through which said valve projects, said third casing having a large bore, and a small bore axially aligned with the large bore, an orifice member disposed between said bores, said valve including a tapered end adapted to project through said orifice and to vary the opening thereof, a fuel inlet opening formed in said third casing and communicating with said small bore, an outlet opening formed in said .third casing and communicating with said large bore, means for sealing the large bore in said third casing from the actuating chamber in the subadjacent casing, an axially adjustable plug member threadably mounted in one of said casings and having an annular scat formed thereon, a retaining member disposed in the actuating chamber associated with said plug, a spring member disposed intermediate said annular seat and the retaining member for urging said diaphragm and valve toward an orifice closing position, stop means for limiting the closing movement of said valve, means mounted on and axially adjustable relative to said plug for axially engaging said valve element to limit the opening movement thereof, passage means formed in one of said casings and adapted to communicate a force to the associated actuating chamber which is proportional to the mass of air flowing through said engine to move said valve toward a closed position, and a passage formed in the other of said dish shaped members and communicating the opposite side of said diaphragm with manifold vacuum to move said valve toward an open position as manifold vacuum increases.

References Cited in the file of this patent UNITED STATES PATENTS 1,394,687 Reid Oct. 25, 1921 1,841,778 Beatson Jan. 19, 1932 2,132,445 Schweizer Oct. 11, 1938 2,136,959 Winfield Nov. 15, 1938 2,374,844 Stokes May 1, 1945 2,414,322 Mock Jan. 14, 1947 2,673,556 Reggio Mar. 30, 1954 

